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To decrease the injury caused by an accidental collision between the hydraulic manipulator and human, a hydraulic rotating angle self-servo compliant robot driver joint is designed. Based on this joint, a variable stiffness passive servo-hydraulic rotary joint is improved. The passive follow-up characteristics of the improved servo-hydraulic rotary joint enable it to enter the low stiffness mode by itself when it encounters collisions beyond the force limit. Combining this characteristic, the research method of the hydraulic mechanical arm flexible configuration is proposed. Firstly, the joint motion mode is defined by the Euler angle, and a variety of configurations conforming to the motion characteristics of the manipulator are determined. Then, the virtual prototype and collision environment are built, and the dynamic characteristics of the end effector of the arm under high and low stiffness are measured. The results show that the flexible configurations with passive follow-up characteristics can significantly suppress the collision force. Finally, the visual method is employed to solve, draw, and compare the workspace of the selected compliant configuration, to obtain the optimal compliant configuration with both flexibility and motion, which provides theoretical guidance for the subsequent design of the compliant manipulator.

To realise the resonant characteristics of motor drive system, a wavelet multiresolution filter (WMF)-based scheme is proposed in this study to perform the detection of the mechanical resonant frequencies for interior permanent magnet synchronous motor servo drives. In a conventional motor drive system, the compliance in the coupling between motor and load may cause resonance. Moreover, the parasitic torque ripples resulting from the harmonics of a pulse-width modulation inverter may excite mechanical vibrations. In the proposed scheme, the localisation analysis of signal can be completed with the WMF at any time and frequency domains for the extraction of resonant frequencies. Then, a band-pass filter is applied to perform the frequency sweeping for the detection of resonant frequencies. In the final stage, the signal smoothing is implemented with the calculation of absolute and average values. To verify the effectiveness of the proposed resonant-frequency detection scheme using the WMF, some experimental results at different rotor speed and load conditions are provided. In addition, a two-channel dynamic signal analyser is also adopted in the experimentation for the comparison of resonant-frequency detection.

In this paper two axis sun tracking method is used to absorb maximum power from the sun's rays on the solar panel via calculating the sun’s altitude and azimuth angles, which describe the solar position on the Iraqi capital Baghdad for the hours 6:00, 7:00, 8:00, 9:00, 12:00, 15:00 and 17:00 per day. The angles were calculated in an average approach within one month, so certain values were determined for each month. The daily energy achieved was calculated for the solar tracking method compared with the fixed tracking method. Designed, modeled and simulated a control circuit consisting of reference position truth table, PI Controller and two servomotors that tracked the sun position to adjust the PV panel perpendicular on the rays of the sun. The results obtained by a simulation software MATLAB/Simulink.

The problem of controlling a typical nonlinear servo motor of an unmanned aercraft with non-stationary parameters using a robust PID controller is considered. The procedure for calculating the parameters of a robust PID controller based on the localization method (further - LM PID controller) for continuous and discrete control systems is studied. The influence of disturbing factors (internal and external) acting on the servo motor is considered. It is established that the main perturbations acting on the servo drive include internal perturbations, which are changes in the time constant and its gain from the temperature of the environment and the quality of the supply voltage. The simulation in the class of linear and nonlinear continuous systems showed that a servo drive with a ML PID controller has the property of robustness in the working range of changes in both the input signal and the parameters of the servo drive and controller. Simulation results showing the research are presented. When describing a servo motor with an LM PID controller in the class of linear discrete systems, its robustness is limited by a narrow range of variation of both its parameters and the quantization period of the input signal. As the degree of uncertainty in the parameters of the servo motor increases (approaching the working range of their change), the discrete system loses stability. For the synthesis of robust control circuits of an unmanned aercraft with given characteristics, mathematical dependences of the settling time and static error of a typical servo motor with LM PID controller from the quantization period of the input signal and the degree of uncertainty in its parameters are presented.

Most of classical adaptive laws used in adaptive control have been developed based on the gradient descent algorithm to minimize the control error. Hence, the sluggish convergence of tracking error may affect the online learning, making accurate parameter estimation difficult. The aim of this article is to present a new adaptive law to achieve optimal parameter estimation, and then to showcase its application to adaptive control for a benchmark servo system to retain simultaneous convergence of both the estimation error and tracking error. For this purpose, an auxiliary filter is introduced to extract the estimation error, which is used to drive the adaptive law with a time-varying gain to minimize a cost function of the estimation error to achieve fast, accurate parameter estimation. Finally, this new adaptation is incorporated into an adaptive nonsingular terminal sliding-mode control for the considered servo system to obtain tracking control and parameter estimation simultaneously. The effectiveness of the developed method is validated by means of comparative simulations and experiments.

This paper presents the design, modelling, control, and experimental validation of a novel flapping wing aerial robot built with servo actuators that could be applied in search, rescue, and assistance to injured people. The proposed concept design is intended to facilitate the construction of this kind of aerial robots following a modular and reconfigurable approach, consisting of a series of Servo-Flapping Engine (SFE) modules attached to the carbon fibre tube used as fuselage, and a tail servo, covering the structure with a light nylon cloth. The SFE modules are built with a pair of servos that rotate the wing rods with desired amplitude, frequency, and relative phase. Combining two SFE modules, it is possible to generate different flapping patterns and control the orientation of the aerodynamic surfaces. The paper covers the parametrization of the design, the hardware/software implementation, as well as the modelling and control. The proposed design is validated through gliding and flapping tests in an outdoor environment. Comisión Europea - ERC Advanced Grant GRIFFIN Action 788247 Comisión Europea - Proyecto AERIAL-CORE H2020-2019-871479

Due to the uncertainties caused by high non-linearity, friction, leakage and other external factors existing in the flight simulator with continuous rotary electro-hydraulic servo motor and the traditional control strategies discontenting with the high-performance requirements, the mathematical model of continuous rotary electro-hydraulic position servo system is established and the compound control theory combining proportional-integral-derivative (PID) and the predictive function control (PFC) method is proposed. In order to enable the servo system to estimate the influence of uncertainties and correct it by repeating online optimisation continuously, PID–PFC compound controller basing on the structure of internal model control is designed and then applied to continuous rotary electro hydraulic servo system. The simulation results show that compared with the traditional PID, PFC controller, PID–PFC compound control can effectively inhibit the interferences of the electro-hydraulic servo system, and greatly improve the response speed and tracking performances and expanding the system frequency band width. The accurate control of motor's position can be realised by applying PID–PFC compound control, which can make the servo system has stronger robustness.

In order to improve the robustness and low-speed performance of continuous rotary electro-hydraulic servo system under influences of dynamic uncertainties, parametric perturbation, friction, other non-linear properties, and uncertainties, the robust control strategy was proposed with Adaboost prediction. Firstly, basing on the system mathematic model, the model with structured uncertainty and generalised state equation was established with parametric perturbation and external disturbances, and then the robust controller was developed by adopting [inline-formula] theory. Furthermore, Adaboost algorithm based on radial basis function (RBF) neural network was applied to design the system feedback mechanism, so the multiple weak neural network learners were obtained by using Adaboost algorithm to train system actual output and input. Also, these weak neural network learners constituted a strong learner to predict the electro-hydraulic servo system output and calculate the predictive error so as to adjust the system robust control output, so the real-time control was carried out by the robust controller. Some comparative simulated results are obtained to verify the proposed controller guarantees performances of low speed, tracking accuracy, and ability of anti-interference, which greatly expands the band of frequency response and improve the system robustness.

This paper deals with an analytical model of reluctance synchronous motor, able to consider both stator slotting effect and magnetic saturation in the stator and rotor iron paths. It joints the field distribution at the air gap to a lumped-parameter magnetic network. Local saturation factors are defined so as to adjust the flux-density distribution. The analytical approach exhibits great potentiality, since it is a formulation based on an harmonic study, and it is easily adaptable to any motor geometries. As an example, 36-slot 4-pole machine is analyzed, considering three flux barriers per pole. Finite element analysis confirms the results achieved by means of the analytical model.

Ultrahigh-precision tracking in nanomanipulations poses major challenges for mechanical design as well as servo control, due to the general confliction between the precision requirement and large stroke tracking. The situation is further complicated by input saturation, which is almost inevitable for microactuators. This paper presents a novel control architecture combining a parallel internal-model-based tracking design and a robust antiwindup control structure, such that asymptotic tracking can be achieved for nanoservo systems in the presence of saturation nonlinearity and model uncertainties. For the augmented system with internal-model dynamics, an I/O-based equivalent representation from control (free of saturation) to system output is derived by incorporating the dead-zone nonlinearity, saturation compensation blocks, as well internal-model units. The robustness condition on the saturation compensator is also derived based on the sector bound criterion and an $\mathcal {H}_\infty$ -optimal design is developed accordingly. The proposed robust antiwindup tracking control architecture is deployed on a customize-designed nanostage driven by a piezoelectric (PZT) actuator, where numerical simulations and real-time experiments demonstrate excellent tracking performance and saturation compensation capability, achieving tracking precision error less than $0.23\%$ .

The paper presents an automatic parameter identification procedure for linear permanent magnet synchronous motors. The electrical parameters of a test machine are estimated by identification tests performed through the inverter. The method employs the available feedback signals that are needed by the control. The stator resistance and machine inductances are estimated through signal injection at standstill. The permanent magnets' flux-linkage identification instead requires carriage movement. Subsequently, the inverter nonlinearity characteristics are identified, again at standstill, through a flux-observer. The proposed self-commissioning process requires only the nameplate data of the machine and no datasheet information of the power electronic devices is needed. The developed techniques can be used both with and without a position sensor. The complete process is automatic and safe to run on its own and requires least intervention from the operator.

La Freescale Cup és una competició de cotxes autònoms en la qual els estudiants de diferents universitats, tots amb el mateix cotxe que proporciona Freescale, programen un algorisme de comportament que fa que aquest cotxe sigui capaç de recórrer un circuit marcat per una línia negra sense cap tipus de comandament humà directe. En aquest article veurem com vam desenvolupar el treball per tal de programar el nostre propi algorisme de funcionament autònom per al cotxe que s'utilitza en aquesta competició i com vam crear un programa per a comprovar que tots els components físics del vehicle funcionen correctament així com una API per a facilitar una possible programació d'altres algorismes en un futur. Per a realitzar aquestes tasques, vam recórrer a fonts externes per a obtenir les dades dels components físics que disposàvem així com fragments de codi per a fer funcionar cadascun d'aquests individualment i els vam sintetitzar en un codi únic que era capaç de fer funcionar tots aquests a la vegada. Fet això, es va programar l'API per a facilitar l'última part del projecte, la programació de l'algorisme final de comportament autònom. Finalment, vam aconseguir que el cotxe seguís el circuit marcat amb la pròpia API, havent superat diferents obstacles sorgits durant el projecte, amb un resultat final satisfactori. The Freescale Cup is an autonomous car competition where students from many universities must programme a behaviour algorithm to steer a car provided by Freescale. This algorithm makes the car navigate through a track by following a black line and without any direct human control. In this article, we will examine how we carried out this project to program our own autonomous operating algorithm for the car used in this competition and how we created the software to check that all the physical components of the vehicle were working properly, as well as an API to facilitate other algorithm programming in the future. To achieve these tasks, we made use of external sources to obtain information about the physical components we had and code snippets to operate each of them individually. Then we synthesize these code snippets in a unique code that made all the components work at the same time. Having done so, we programmed the API to facilitate the last part of the project: the programming of the autonomous behaviour final algorithm. Finally, we made the car follow the marked circuit with its own API. So, having overcome several obstacles encountered throughout the project, the result was satisfactory. La Freescale Cup es una competición de coches autónomos en la cual los estudiantes de diferentes universidades, todos con el mismo coche que proporciona Freescale, programan un algoritmo de comportamiento que hace que este coche sea capaz de recorrer un circuito marcado por una línea negra sin ningún tipo de orden humana directa. En este artículo veremos cómo desarrollamos el trabajo para programar nuestro propio algoritmo de funcionamiento autónomo para el coche que se utiliza en esta competición y cómo creamos un programa para comprobar que todos los componentes físicos del vehículo funcionan correctamente así como una API para facilitar una posible programación de otros algoritmos en un futuro. Para realizar estas tareas, recurrimos a fuentes externas para obtener los datos de los componentes físicos que disponíamos así como fragmentos de código para hacer funcionar cada uno de estos individualmente y los sintetizamos en un código único que era capaz de hacer funcionar todos estos a la vez. Hecho esto, se programó la API para facilitar la última parte del proyecto, la programación del algoritmo final de comportamiento autónomo. Finalmente, conseguimos que el coche siguiera el circuito marcado con la propia API, habiendo superado diferentes obstáculos surgidos durante el proyecto, con un resultado final satisfactorio.

This study presents a stand-alone excitation synchronous wind power generator (SESWPG) with power flow management strategy (PFMS). The rotor speed of the excitation synchronous generator tracks the utility grid frequency by using servo motor tracking technologies. The automatic voltage regulator governs the exciting current of generator to achieve the control goals of stable voltage. When wind power is less than the needs of the consumptive loading, the proposed PFMS increases motor torque to provide a positive power output for the loads, while keeping the generator speed constant. Conversely, during the periods of wind power greater than output loads, the redundant power of generator production is charged to the battery pack and the motor speed remains constant with very low power consumption. The advantage of the proposed SESWPG is that the generator can directly output stable alternating current (AC) electricity without using additional DC–AC converters. The operation principles with software simulation for the system are described in detail. Experimental results of a laboratory prototype are shown to verify the feasibility of the system.

Performance of an electrohydraulic impedance controller, developed in the physical domain, for controlling the contact forces during robotic interaction tasks is analyzed in this paper. The impedance controller is capable of varying the mechanical impedance of the manipulator during an interaction task and thus controls the interaction force. An electrohydraulic servo actuator, appended to a 1-d.o.f. manipulator arm, acts as the controller in the physical domain. The controller performance depends on the physical parameters such as size of the actuator, bulk modulus of the oil, etc., of the hydraulic system. The influence of these physical parameters of the controller performance is analyzed through frequency analysis and acceptable ranges of values for these parameters are determined. Controller sensitivity, stability of the constrained manipulator system and its frequency response are analyzed theoretically and results are presented. The limitation of application of the controller for practical applications is also analyzed and the results are presented.

This work deals with the modeling, control and experimental validation of a flywheel test bench which is part of IREC’s lab-scale microgrid. The storage device has been designed as a proof of concept. It is based on a low-speed rotating disk mechanically coupled to a Permanent Magnet Synchronous Machine. The electrical power is exchanged with the external grid by means of a set of back-to-back power converters. These power electronics control the speed of the machine, and thus the active power absorbed or injected by the device, and also regulate the reactive power at the point of common coupling with the external grid. Vector control techniques are used for designing the converter controllers: a field oriented vector control algorithm is implemented for governing the servomotor while the instantaneous power theory-based algorithm is used to manage the active and reactive currents flowing from the grid side converter. The control implementation in the experimental setup has been carried out by means of programming Digital Signal Processors (DSP’s). The modeling and control system design has been validated after executing several experiments.

In this paper, we present the design and construction of a prototype target tracking system. The experimental set up consists of three main modules for moving the object, detecting the motion of the object and its tracking. The mechanism for moving the object includes an object and two stepper motors and their driving and control circuitry. The detection of the object’s motion is realized by photo switch array. The tracking mechanism consists of a laser beam and two DC servomotors and their associated circuitry. The control algorithm is a standard fuzzy logic controller. The system is designed to operate in two modes in such a way that the role of target and tracker can be interchanged. Experimental results indicate that the fuzzy controller is capable of controlling the system in both modes.

This paper presents a simple technique to minimize torque ripple of a switched reluctance motor. The technique is based on the control of the sum of the square of the phase currents by using only two current sensors and analog multipliers. The simulation results and a proposed circuit are given. The advantages and its limitations of the proposed circuit are explained. >

The emerging measurement technology of phasor measurement units (PMUs) makes it possible to estimate the state of electrical grids in real-time, thus opening the way to new protection and control applications. PMUs rely on precise time synchronization, therefore they are vulnerable to timesynchronization attacks which alter the measured voltage and current phases. In particular, undetectable time synchronization attacks pose a significant threat as they lead to an incorrect but credible estimate of the system state. Prior work has shown that such attacks exist against pairs of PMUs, but they do not take into consideration the clock adjustment performed by the clockservo, which can modify the attack angles and make the attacks detectable. This cannot easily be addressed with the existing attacks, as the undetectable angle values form a discrete set and cannot be continuously adjusted as would be required to address the problems posed to the attacker by the clock servo. Going beyond prior work, this paper first shows how to perform undetectable attacks against more than two PMUs, so that the set of undetectable attacks forms a continuum and supports small adjustments. Second, it shows how an attacker can anticipate the operation of the clock servo while achieving her attack goal and remaining undetectable. Third, the paper shows how to identify vulnerable sets of PMUs. Numerical results on the 39-bus IEEE benchmark system illustrate the feasibility of the proposed attack strategies.

A new type of pneumatic stepping motor, named pneumatic nutation motor, was developed. This motor achieves stepping positioning of 720 steps/rotation without any electrical devices or sensors mounted on the servo mechanisms. This makes the motor possible to be used under hazardous conditions such as in water and in strong magnetic fields where conventional electromagnetic motors cannot be used. The motor torque is so big that the motor can be used as a direct motor. In this report, the driving principle and design of this motor are presented. Its characteristics are analyzed experimentally and theoretically. The motors were applied to a parallel linkage mechanism with six degrees of freedom. The mechanism shows that the pneumatic nutation motors can be used as a direct servo motor for robot mechanisms.

This paper presents the modeling, simulation and analysis of the dynamic behavior of a hydroelectric power plant of 2×343 MVA including hydraulic system, electrical installations, rotating inertias and control systems. First, the modeling of the electrical and hydraulic systems is described. The electrical system is constituted by a salient-pole synchronous generator with its ST1A excitation system model and PSS2B power system stabilizer model. Then, the set of parameters of the turbine speed governor of the hydroelectric power plant is determined with a specific identification procedure to achieve stable operation for different cases as interconnected or isolated operation. The analysis of the stability of the power plant is investigated through time domain simulations for different sets of controllers' parameters and for different cases (simulation of the only electric part and of the whole hydroelectric system).

In this paper, we present an integrator-differentiator transimpedance amplifier (TIA) featuring a multielement pseudo-resistor (MEPR) in the DC feedback path for improved noise performance in the presence of non-zero DC input currents. The presented prototype is implemented in a standard 180 nm CMOS technology and achieves an inband transimpedance of 10 M Omega over a 2.7 MHz signal bandwidth. The MEPR resistor in the DC servo loop can be tuned between 700 k Omega and 100 M Omega enabling a precise adjustment of the TIA's lower cutoff frequency. For a DC feedback resistance of 700 k Omega, the TIA provides an input referred noise floor of 180 fA/root Hz at zero input current, which only marginally increases to 220 fA/root Hz for the maximum bias current of 1 mu A. The TIA consumes 0.6 mm(2) of chip area and 18.5 mW of power from a 1.8 V supply.